I bought one this year. It was the Benz. My experience with it was that it did almost eliminate all of the exhaust noise, but these little machines make a LOT of noise. The engine makes plenty of noise and the tires rolling along on a gravel road make a lot of noise. But now I can hear all of those noises because the exhaust noise doesn't drown them out. As far as how it affects the critters, I haven't used it enough to really make any judgements. I think a lot of that is determined by how habituated the critters are with ATV and other machinery. So far the few deer I ran across just stood and stared at me. But the big thing is I just wanted it quieter for my own peace of mind and sanity, if it distresses the critters less that's just a bonus. So I guess I'd do it again, but if you think putting one of these things on will eliminate all the noise you'll be disappointed, but it does cut down on a bunch (technical term) the noise.